/*
 * jcmarker.c
 *
 * Copyright (C) 1991-1995, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains routines to write JPEG datastream markers.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"


typedef enum
{								/* JPEG marker codes */
	M_SOF0 = 0xc0,
	M_SOF1 = 0xc1,
	M_SOF2 = 0xc2,
	M_SOF3 = 0xc3,

	M_SOF5 = 0xc5,
	M_SOF6 = 0xc6,
	M_SOF7 = 0xc7,

	M_JPG = 0xc8,
	M_SOF9 = 0xc9,
	M_SOF10 = 0xca,
	M_SOF11 = 0xcb,

	M_SOF13 = 0xcd,
	M_SOF14 = 0xce,
	M_SOF15 = 0xcf,

	M_DHT = 0xc4,

	M_DAC = 0xcc,

	M_RST0 = 0xd0,
	M_RST1 = 0xd1,
	M_RST2 = 0xd2,
	M_RST3 = 0xd3,
	M_RST4 = 0xd4,
	M_RST5 = 0xd5,
	M_RST6 = 0xd6,
	M_RST7 = 0xd7,

	M_SOI = 0xd8,
	M_EOI = 0xd9,
	M_SOS = 0xda,
	M_DQT = 0xdb,
	M_DNL = 0xdc,
	M_DRI = 0xdd,
	M_DHP = 0xde,
	M_EXP = 0xdf,

	M_APP0 = 0xe0,
	M_APP1 = 0xe1,
	M_APP2 = 0xe2,
	M_APP3 = 0xe3,
	M_APP4 = 0xe4,
	M_APP5 = 0xe5,
	M_APP6 = 0xe6,
	M_APP7 = 0xe7,
	M_APP8 = 0xe8,
	M_APP9 = 0xe9,
	M_APP10 = 0xea,
	M_APP11 = 0xeb,
	M_APP12 = 0xec,
	M_APP13 = 0xed,
	M_APP14 = 0xee,
	M_APP15 = 0xef,

	M_JPG0 = 0xf0,
	M_JPG13 = 0xfd,
	M_COM = 0xfe,

	M_TEM = 0x01,

	M_ERROR = 0x100
} JPEG_MARKER;


/*
 * Basic output routines.
 *
 * Note that we do not support suspension while writing a marker.
 * Therefore, an application using suspension must ensure that there is
 * enough buffer space for the initial markers (typ. 600-700 bytes) before
 * calling jpeg_start_compress, and enough space to write the trailing EOI
 * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
 * modes are not supported at all with suspension, so those two are the only
 * points where markers will be written.
 */

LOCAL void emit_byte(j_compress_ptr cinfo, int val)
/* Emit a byte */
{
	struct jpeg_destination_mgr *dest = cinfo->dest;

	*(dest->next_output_byte)++ = (JOCTET) val;
	if(--dest->free_in_buffer == 0)
	{
		if(!(*dest->empty_output_buffer) (cinfo))
			ERREXIT(cinfo, JERR_CANT_SUSPEND);
	}
}


LOCAL void emit_marker(j_compress_ptr cinfo, JPEG_MARKER mark)
/* Emit a marker code */
{
	emit_byte(cinfo, 0xFF);
	emit_byte(cinfo, (int)mark);
}


LOCAL void emit_2bytes(j_compress_ptr cinfo, int value)
/* Emit a 2-byte integer; these are always MSB first in JPEG files */
{
	emit_byte(cinfo, (value >> 8) & 0xFF);
	emit_byte(cinfo, value & 0xFF);
}


/*
 * Routines to write specific marker types.
 */

LOCAL int emit_dqt(j_compress_ptr cinfo, int index)
/* Emit a DQT marker */
/* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
{
	JQUANT_TBL     *qtbl = cinfo->quant_tbl_ptrs[index];
	int             prec;
	int             i;

	if(qtbl == NULL)
		ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);

	prec = 0;
	for(i = 0; i < DCTSIZE2; i++)
	{
		if(qtbl->quantval[i] > 255)
			prec = 1;
	}

	if(!qtbl->sent_table)
	{
		emit_marker(cinfo, M_DQT);

		emit_2bytes(cinfo, prec ? DCTSIZE2 * 2 + 1 + 2 : DCTSIZE2 + 1 + 2);

		emit_byte(cinfo, index + (prec << 4));

		for(i = 0; i < DCTSIZE2; i++)
		{
			if(prec)
				emit_byte(cinfo, qtbl->quantval[i] >> 8);
			emit_byte(cinfo, qtbl->quantval[i] & 0xFF);
		}

		qtbl->sent_table = TRUE;
	}

	return prec;
}


LOCAL void emit_dht(j_compress_ptr cinfo, int index, boolean is_ac)
/* Emit a DHT marker */
{
	JHUFF_TBL      *htbl;
	int             length, i;

	if(is_ac)
	{
		htbl = cinfo->ac_huff_tbl_ptrs[index];
		index += 0x10;			/* output index has AC bit set */
	}
	else
	{
		htbl = cinfo->dc_huff_tbl_ptrs[index];
	}

	if(htbl == NULL)
		ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);

	if(!htbl->sent_table)
	{
		emit_marker(cinfo, M_DHT);

		length = 0;
		for(i = 1; i <= 16; i++)
			length += htbl->bits[i];

		emit_2bytes(cinfo, length + 2 + 1 + 16);
		emit_byte(cinfo, index);

		for(i = 1; i <= 16; i++)
			emit_byte(cinfo, htbl->bits[i]);

		for(i = 0; i < length; i++)
			emit_byte(cinfo, htbl->huffval[i]);

		htbl->sent_table = TRUE;
	}
}


LOCAL void emit_dac(j_compress_ptr cinfo)
/* Emit a DAC marker */
/* Since the useful info is so small, we want to emit all the tables in */
/* one DAC marker.  Therefore this routine does its own scan of the table. */
{
#ifdef C_ARITH_CODING_SUPPORTED
	char            dc_in_use[NUM_ARITH_TBLS];
	char            ac_in_use[NUM_ARITH_TBLS];
	int             length, i;
	jpeg_component_info *compptr;

	for(i = 0; i < NUM_ARITH_TBLS; i++)
		dc_in_use[i] = ac_in_use[i] = 0;

	for(i = 0; i < cinfo->comps_in_scan; i++)
	{
		compptr = cinfo->cur_comp_info[i];
		dc_in_use[compptr->dc_tbl_no] = 1;
		ac_in_use[compptr->ac_tbl_no] = 1;
	}

	length = 0;
	for(i = 0; i < NUM_ARITH_TBLS; i++)
		length += dc_in_use[i] + ac_in_use[i];

	emit_marker(cinfo, M_DAC);

	emit_2bytes(cinfo, length * 2 + 2);

	for(i = 0; i < NUM_ARITH_TBLS; i++)
	{
		if(dc_in_use[i])
		{
			emit_byte(cinfo, i);
			emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i] << 4));
		}
		if(ac_in_use[i])
		{
			emit_byte(cinfo, i + 0x10);
			emit_byte(cinfo, cinfo->arith_ac_K[i]);
		}
	}
#endif							/* C_ARITH_CODING_SUPPORTED */
}


LOCAL void emit_dri(j_compress_ptr cinfo)
/* Emit a DRI marker */
{
	emit_marker(cinfo, M_DRI);

	emit_2bytes(cinfo, 4);		/* fixed length */

	emit_2bytes(cinfo, (int)cinfo->restart_interval);
}


LOCAL void emit_sof(j_compress_ptr cinfo, JPEG_MARKER code)
/* Emit a SOF marker */
{
	int             ci;
	jpeg_component_info *compptr;

	emit_marker(cinfo, code);

	emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1);	/* length */

	/* Make sure image isn't bigger than SOF field can handle */
	if((long)cinfo->image_height > 65535L || (long)cinfo->image_width > 65535L)
		ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)65535);

	emit_byte(cinfo, cinfo->data_precision);
	emit_2bytes(cinfo, (int)cinfo->image_height);
	emit_2bytes(cinfo, (int)cinfo->image_width);

	emit_byte(cinfo, cinfo->num_components);

	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		emit_byte(cinfo, compptr->component_id);
		emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
		emit_byte(cinfo, compptr->quant_tbl_no);
	}
}


LOCAL void emit_sos(j_compress_ptr cinfo)
/* Emit a SOS marker */
{
	int             i, td, ta;
	jpeg_component_info *compptr;

	emit_marker(cinfo, M_SOS);

	emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3);	/* length */

	emit_byte(cinfo, cinfo->comps_in_scan);

	for(i = 0; i < cinfo->comps_in_scan; i++)
	{
		compptr = cinfo->cur_comp_info[i];
		emit_byte(cinfo, compptr->component_id);
		td = compptr->dc_tbl_no;
		ta = compptr->ac_tbl_no;
		if(cinfo->progressive_mode)
		{
			/* Progressive mode: only DC or only AC tables are used in one scan;
			 * furthermore, Huffman coding of DC refinement uses no table at all.
			 * We emit 0 for unused field(s); this is recommended by the P&M text
			 * but does not seem to be specified in the standard.
			 */
			if(cinfo->Ss == 0)
			{
				ta = 0;			/* DC scan */
				if(cinfo->Ah != 0 && !cinfo->arith_code)
					td = 0;		/* no DC table either */
			}
			else
			{
				td = 0;			/* AC scan */
			}
		}
		emit_byte(cinfo, (td << 4) + ta);
	}

	emit_byte(cinfo, cinfo->Ss);
	emit_byte(cinfo, cinfo->Se);
	emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
}


LOCAL void emit_jfif_app0(j_compress_ptr cinfo)
/* Emit a JFIF-compliant APP0 marker */
{
	/*
	 * Length of APP0 block   (2 bytes)
	 * Block ID           (4 bytes - ASCII "JFIF")
	 * Zero byte          (1 byte to terminate the ID string)
	 * Version Major, Minor   (2 bytes - 0x01, 0x01)
	 * Units          (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
	 * Xdpu           (2 bytes - dots per unit horizontal)
	 * Ydpu           (2 bytes - dots per unit vertical)
	 * Thumbnail X size       (1 byte)
	 * Thumbnail Y size       (1 byte)
	 */

	emit_marker(cinfo, M_APP0);

	emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1);	/* length */

	emit_byte(cinfo, 0x4A);		/* Identifier: ASCII "JFIF" */
	emit_byte(cinfo, 0x46);
	emit_byte(cinfo, 0x49);
	emit_byte(cinfo, 0x46);
	emit_byte(cinfo, 0);
	/* We currently emit version code 1.01 since we use no 1.02 features.
	 * This may avoid complaints from some older decoders.
	 */
	emit_byte(cinfo, 1);		/* Major version */
	emit_byte(cinfo, 1);		/* Minor version */
	emit_byte(cinfo, cinfo->density_unit);	/* Pixel size information */
	emit_2bytes(cinfo, (int)cinfo->X_density);
	emit_2bytes(cinfo, (int)cinfo->Y_density);
	emit_byte(cinfo, 0);		/* No thumbnail image */
	emit_byte(cinfo, 0);
}


LOCAL void emit_adobe_app14(j_compress_ptr cinfo)
/* Emit an Adobe APP14 marker */
{
	/*
	 * Length of APP14 block  (2 bytes)
	 * Block ID           (5 bytes - ASCII "Adobe")
	 * Version Number     (2 bytes - currently 100)
	 * Flags0         (2 bytes - currently 0)
	 * Flags1         (2 bytes - currently 0)
	 * Color transform        (1 byte)
	 *
	 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
	 * now in circulation seem to use Version = 100, so that's what we write.
	 *
	 * We write the color transform byte as 1 if the JPEG color space is
	 * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
	 * whether the encoder performed a transformation, which is pretty useless.
	 */

	emit_marker(cinfo, M_APP14);

	emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1);	/* length */

	emit_byte(cinfo, 0x41);		/* Identifier: ASCII "Adobe" */
	emit_byte(cinfo, 0x64);
	emit_byte(cinfo, 0x6F);
	emit_byte(cinfo, 0x62);
	emit_byte(cinfo, 0x65);
	emit_2bytes(cinfo, 100);	/* Version */
	emit_2bytes(cinfo, 0);		/* Flags0 */
	emit_2bytes(cinfo, 0);		/* Flags1 */
	switch (cinfo->jpeg_color_space)
	{
		case JCS_YCbCr:
			emit_byte(cinfo, 1);	/* Color transform = 1 */
			break;
		case JCS_YCCK:
			emit_byte(cinfo, 2);	/* Color transform = 2 */
			break;
		default:
			emit_byte(cinfo, 0);	/* Color transform = 0 */
			break;
	}
}


/*
 * This routine is exported for possible use by applications.
 * The intended use is to emit COM or APPn markers after calling
 * jpeg_start_compress() and before the first jpeg_write_scanlines() call
 * (hence, after write_file_header but before write_frame_header).
 * Other uses are not guaranteed to produce desirable results.
 */

METHODDEF void write_any_marker(j_compress_ptr cinfo, int marker, const JOCTET * dataptr, unsigned int datalen)
/* Emit an arbitrary marker with parameters */
{
	if(datalen <= (unsigned int)65533)
	{							/* safety check */
		emit_marker(cinfo, (JPEG_MARKER) marker);

		emit_2bytes(cinfo, (int)(datalen + 2));	/* total length */

		while(datalen--)
		{
			emit_byte(cinfo, *dataptr);
			dataptr++;
		}
	}
}


/*
 * Write datastream header.
 * This consists of an SOI and optional APPn markers.
 * We recommend use of the JFIF marker, but not the Adobe marker,
 * when using YCbCr or grayscale data.  The JFIF marker should NOT
 * be used for any other JPEG colorspace.  The Adobe marker is helpful
 * to distinguish RGB, CMYK, and YCCK colorspaces.
 * Note that an application can write additional header markers after
 * jpeg_start_compress returns.
 */

METHODDEF void write_file_header(j_compress_ptr cinfo)
{
	emit_marker(cinfo, M_SOI);	/* first the SOI */

	if(cinfo->write_JFIF_header)	/* next an optional JFIF APP0 */
		emit_jfif_app0(cinfo);
	if(cinfo->write_Adobe_marker)	/* next an optional Adobe APP14 */
		emit_adobe_app14(cinfo);
}


/*
 * Write frame header.
 * This consists of DQT and SOFn markers.
 * Note that we do not emit the SOF until we have emitted the DQT(s).
 * This avoids compatibility problems with incorrect implementations that
 * try to error-check the quant table numbers as soon as they see the SOF.
 */

METHODDEF void write_frame_header(j_compress_ptr cinfo)
{
	int             ci, prec;
	boolean         is_baseline;
	jpeg_component_info *compptr;

	/* Emit DQT for each quantization table.
	 * Note that emit_dqt() suppresses any duplicate tables.
	 */
	prec = 0;
	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		prec += emit_dqt(cinfo, compptr->quant_tbl_no);
	}
	/* now prec is nonzero iff there are any 16-bit quant tables. */

	/* Check for a non-baseline specification.
	 * Note we assume that Huffman table numbers won't be changed later.
	 */
	if(cinfo->arith_code || cinfo->progressive_mode || cinfo->data_precision != 8)
	{
		is_baseline = FALSE;
	}
	else
	{
		is_baseline = TRUE;
		for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
		{
			if(compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
				is_baseline = FALSE;
		}
		if(prec && is_baseline)
		{
			is_baseline = FALSE;
			/* If it's baseline except for quantizer size, warn the user */
			TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
		}
	}

	/* Emit the proper SOF marker */
	if(cinfo->arith_code)
	{
		emit_sof(cinfo, M_SOF9);	/* SOF code for arithmetic coding */
	}
	else
	{
		if(cinfo->progressive_mode)
			emit_sof(cinfo, M_SOF2);	/* SOF code for progressive Huffman */
		else if(is_baseline)
			emit_sof(cinfo, M_SOF0);	/* SOF code for baseline implementation */
		else
			emit_sof(cinfo, M_SOF1);	/* SOF code for non-baseline Huffman file */
	}
}


/*
 * Write scan header.
 * This consists of DHT or DAC markers, optional DRI, and SOS.
 * Compressed data will be written following the SOS.
 */

METHODDEF void write_scan_header(j_compress_ptr cinfo)
{
	int             i;
	jpeg_component_info *compptr;

	if(cinfo->arith_code)
	{
		/* Emit arith conditioning info.  We may have some duplication
		 * if the file has multiple scans, but it's so small it's hardly
		 * worth worrying about.
		 */
		emit_dac(cinfo);
	}
	else
	{
		/* Emit Huffman tables.
		 * Note that emit_dht() suppresses any duplicate tables.
		 */
		for(i = 0; i < cinfo->comps_in_scan; i++)
		{
			compptr = cinfo->cur_comp_info[i];
			if(cinfo->progressive_mode)
			{
				/* Progressive mode: only DC or only AC tables are used in one scan */
				if(cinfo->Ss == 0)
				{
					if(cinfo->Ah == 0)	/* DC needs no table for refinement scan */
						emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
				}
				else
				{
					emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
				}
			}
			else
			{
				/* Sequential mode: need both DC and AC tables */
				emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
				emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
			}
		}
	}

	/* Emit DRI if required --- note that DRI value could change for each scan.
	 * If it doesn't, a tiny amount of space is wasted in multiple-scan files.
	 * We assume DRI will never be nonzero for one scan and zero for a later one.
	 */
	if(cinfo->restart_interval)
		emit_dri(cinfo);

	emit_sos(cinfo);
}


/*
 * Write datastream trailer.
 */

METHODDEF void write_file_trailer(j_compress_ptr cinfo)
{
	emit_marker(cinfo, M_EOI);
}


/*
 * Write an abbreviated table-specification datastream.
 * This consists of SOI, DQT and DHT tables, and EOI.
 * Any table that is defined and not marked sent_table = TRUE will be
 * emitted.  Note that all tables will be marked sent_table = TRUE at exit.
 */

METHODDEF void write_tables_only(j_compress_ptr cinfo)
{
	int             i;

	emit_marker(cinfo, M_SOI);

	for(i = 0; i < NUM_QUANT_TBLS; i++)
	{
		if(cinfo->quant_tbl_ptrs[i] != NULL)
			(void)emit_dqt(cinfo, i);
	}

	if(!cinfo->arith_code)
	{
		for(i = 0; i < NUM_HUFF_TBLS; i++)
		{
			if(cinfo->dc_huff_tbl_ptrs[i] != NULL)
				emit_dht(cinfo, i, FALSE);
			if(cinfo->ac_huff_tbl_ptrs[i] != NULL)
				emit_dht(cinfo, i, TRUE);
		}
	}

	emit_marker(cinfo, M_EOI);
}


/*
 * Initialize the marker writer module.
 */

GLOBAL void jinit_marker_writer(j_compress_ptr cinfo)
{
	/* Create the subobject */
	cinfo->marker = (struct jpeg_marker_writer *)
		(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(struct jpeg_marker_writer));
	/* Initialize method pointers */
	cinfo->marker->write_any_marker = write_any_marker;
	cinfo->marker->write_file_header = write_file_header;
	cinfo->marker->write_frame_header = write_frame_header;
	cinfo->marker->write_scan_header = write_scan_header;
	cinfo->marker->write_file_trailer = write_file_trailer;
	cinfo->marker->write_tables_only = write_tables_only;
}
